How does Emacs select the "-nw" terminal

[<c.buhtz@posteo.jp>]

Hello,

I am using

GNU Emacs 26.1 (build 2, x86_64-pc-linux-gnu, GTK+ Version 3.24.5) of
2021-01-31, modified by Debian

in Debian 10 (stable).

My question is if and how Emacs itself decide in which terminal
emulation it opens when started via "emacs -nw" in a desktop
environment (e.g. Xfce).
And can I manipulate that?

The background of my question:
When I open the context menu of a file in my Xfce filemanager Thunar
the "Open with..." sub-context-menu offers me "Emacs (GUI)" and "Emacs
(Terminal)".

The later opens emacs in a simple (and ugly) xterm.
The entry in that context menu referes to a .desktop-file
(/usr/share/applications/emacs-term.desktop) with the line

	"Exec=/usr/bin/emacs -nw %F"

xterm is not the default terminal. The default is
"/usr/bin/terminator". I checked that via "update-alternatives --config
x-terminal-emulator".

When I enter "emacs -nw" in my terminator window the emacs opens in
that terminator window. So there is not xterm involved.

So it looks like that emacs ignores the systems default terminal.

What is the background of that behaviour and can I modify it?

Thanks in advance